Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Fortinet (Nasdaq: FTNT) surged as much as 14% in early trading after the company reported fourth-quarter results that easily beat expectations.

So what: Revenue improved 32% to $93.6 million. GAAP per-share earnings came in at $0.20. Analysts were expecting $86.7 million and $0.14, respectively. Billings -- a measure of revenue recognized plus the quarterly change in deferred revenue -- rose 35% in Q4.

Now what: Fortinet is in a good business: securing networks. Its customer list includes Level 3 Networks (Nasdaq: LVLT), which soon will be carrying a lot more video traffic for Netflix. Fortinet's appliances will be there to ensure data is delivered securely.

Is that enough to make the stock appealing at these levels? That's tougher to say. Fortinet trades for more than 60 times projected earnings, or almost four times the long-term growth rate analysts expect. At that level, the stock could take a beating if Fortinet were to fail to throttle expectations in future quarters.

Interested in more info on Fortinet? Add it to your watchlist.

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Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. He didn't own shares in any of the companies mentioned in this article at the time of publication. Check out Tim's portfolio holdings and Foolish writings, or connect with him on Twitter as @milehighfool. You can also get his insights delivered directly to your RSS reader. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool is also on Twitter as @TheMotleyFool. Its disclosure policy is at least 10% better than other disclosure policies.